In adventure mode, a player advances through five tanks. A secret sandbox mode can be accessed when the player wins a silver or a golden trophy, by entering the Konami Code at the main menu screen - it allows full access to unlimited amounts of fish, pets and aliens. Insaniquarium can be played in Adventure, Time Trial, Challenge Mode, or Virtual Tank. The deluxe version of Insaniquarium contains eight different aliens, but in the original Java version there are four. The aliens must be clicked on repeatedly with the mouse pointer in order to defeat them. In addition to feeding fish, the player must protect the fish from aliens that periodically enter the tank and attempt to eat the fish. Each creature must be kept alive by feeding, whether through fish food bought by the player or other species of fish in the tank. Guppies and other fish drop money, which can be collected by the player and used to purchase fish food and upgrades, such as more aquatic creatures, more filling food, and powerful lasers to repel attackers. Players must manage a tank of guppies and other aquatic creatures, each stage begins with two guppies in the tank or one breeder which creates guppies.

The latest version, Insaniquarium Deluxe, was released in Septemfor PC.

Shortly after, a PDA version was released. During development a member of the team purchased a goldfish and examined its movements and behaviour. The first version of the game, developed by Flying Bear Entertainment, is Java-based and available as a free online game.

Popcap games insaniquarium